Course of war
The Kurukshetra war lasted eighteen days. The war was fought only during daylight hours and fighting ceased at sunset. The armies met on a vast field in Kurukshetra and each day of the battle was characterised by numerous indiviual combats as well as mass raids against entire enemy divisions. The victor or the vanquished on each day was determined not by any territories gained, but by the body count. This was a war to the death. The victor was the survivor.
Before the battle
On the first day of the war, as would be on all the other days as well, the Kaurava army stood facing west and the Pandava army stood facing east. The Kaurava army was formed such that it faced all sides: elephants formed its body; the kings, its head; and the steeds, its wings. Bhishma, in consultation with his commanders Drona, Bahlika and Kripa.
The Pandava army was organised by Yudhisthira and Arjuna in the Vajra formation. Because the Pandava army was smaller than the Kaurava's, they decided to employ the tactic of each warrior engaging as many enemies as possible. This involved an element of surprise with the bowmen showering arrows from hidden behind the frontal attackers. The attackers in the front were equipped with short-range weapons like the maces, battle-axes, swords, lances etc.
Ten divisions (Akshaunis) of the Kaurava army were arranged in a formidable phalanx. The eleventh was put under the immediate command of Bhishma, partly to protect him. The safety of the supreme commander Bhishma was centre to Duryodhana's strategy as he had placed all his hope on the great warrior's abilities. Dushasana, the brother of king Duryodhana, was the military officer in-charge for Bhishma's protection.
Before the battle began, Yudhisthira did something unexpected. He suddenly dropped his weapons, took off his armour and started walking towards the Kaurava army with folded hands in prayer. The Pandava brothers and the Kauravas looked on in disbelief, thinking Yudhisthira was surrendering even before the arrow was shot. Soon Yudhisthira's purpose was clear as he fell on Bhishma's feet to seek his blessing for his success. Bhishma, grandfather to both Pandavas and the Kauravas, blessed Yudhisthira.
Yudhisthira returned to his chariot and the battle was ready to commence. Arjuna, seeing his kith and kin arrayed against him, suddenly felt remorse at having to fight and perhaps kill members of his own family.
Krishna, his charioteer, advised him to do his duty and not worry about the consequences. Krishna then revealed his divine form and explained that he is born on earth in each eon, whenever evil rises its head.
This portion of Mahabharata is the famous Bhagavad Gita and is one of the most important Hindu philosophical works